Effect of geological characteristics of coarse aggregates on properties of concrete

Abstract

Aggregate is one of the important constituents in concrete and it occupies 60 to 80% of the volume. They provide body to concrete, reduce shrinkage and also affect economy. Further, it is relatively inexpensive than other constituents and usually it has been considered all along as inert filler material. Therefore, required attention was not focused to realize possible influence of aggregates on properties of concrete. Hence, it is very much necessary to understand more about aggregate to produce the concrete with required characteristics. In fact, characteristics of aggregates significantly influences concrete mix proportioning, properties of fresh concrete and also strength, dimensional stability and durability of concrete. Hence, an attempt has been made in the present work to study effect of geological characteristics of aggregates on properties of concrete. Five types of coarse aggregates such as Grey Granite (GG), Anorthosite (AS), Charnockite (CK), Limestone (LS) and Gneiss (GS) were used in this work to study their geological characteristics and their effect on performance of concrete. The geological characteristics of aggregates such as mineralogical composition, proportion of minerals, texture, structural features etc were studied. Subsequently, concrete mixes were made with various types of aggregates to produce M30, M50 and M80 grade of concrete. The concrete specimens were cast and cured over a period of 28 days. The cured specimens were tested for compressive strength, split tensile strength, flexural strength, modulus of elasticity and impact strength and fracture energy, rupture probability of coarse aggregate RPCA and also structural behavior of concrete newline